[lc-checkins] CVS: linux26/mm filemap.c,1.10,1.11 vmscan.c,1.10,1.11

[Nitin G. <nit...@us...>]

Update of /cvsroot/linuxcompressed/linux26/mm
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv8760/mm

Modified Files:
	filemap.c vmscan.c 
Log Message:
2.6.16: better locking, stable

Index: filemap.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux26/mm/filemap.c,v
retrieving revision 1.10
retrieving revision 1.11
diff -C2 -r1.10 -r1.11
*** filemap.c	25 Mar 2006 18:58:47 -0000	1.10
--- filemap.c	5 Apr 2006 09:36:39 -0000	1.11
***************
*** 30,33 ****
--- 30,36 ----
  #include <linux/security.h>
  #include <linux/syscalls.h>
+ 
+ #include <linux/bit_spinlock.h>
+ 
  #include "filemap.h"
  /*
***************
*** 514,517 ****
--- 517,534 ----
  EXPORT_SYMBOL(__lock_page);
  
+ int chunk_head_wait(void *word)
+ {
+ 	schedule();
+ 	return 0;
+ }
+ EXPORT_SYMBOL(chunk_head_wait);
+ 
+ static inline void wait_on_chunk_head(struct page *ch)
+ {
+ 	might_sleep();
+ 	wait_on_bit(&ch->flags, PG_locked, chunk_head_wait, TASK_UNINTERRUPTIBLE);
+ }
+ EXPORT_SYMBOL(wait_on_chunk_head);
+ 
  /*
   * a rather lightweight function, finding and getting a reference to a
***************
*** 523,541 ****
  	struct page *ch;	// chunk head
  
! 	//read_lock_irq(&mapping->tree_lock);
! 	write_lock_irq(&mapping->tree_lock);
  	page = radix_tree_lookup(&mapping->page_tree, offset);
  	if (page) {
  		if (PageCompressed(page)) {
  			printk("<1> ** Compressed page: %u in find_get_page **\n", offset);
  			ch=page;
! 			page=(struct page *)page_private(ch);
! 			radix_tree_delete(&mapping->page_tree, offset);
! 			radix_tree_insert(&mapping->page_tree, offset, page);
  		}
- 		page_cache_get(page);
  	}
! 	//read_unlock_irq(&mapping->tree_lock);
! 	write_unlock_irq(&mapping->tree_lock);
  	return page;
  }
--- 540,596 ----
  	struct page *ch;	// chunk head
  
! 	read_lock_irq(&mapping->tree_lock);
! 	//write_lock_irq(&mapping->tree_lock);
  	page = radix_tree_lookup(&mapping->page_tree, offset);
  	if (page) {
+ 		page_cache_get(page);
+ 		read_unlock_irq(&mapping->tree_lock);
  		if (PageCompressed(page)) {
  			printk("<1> ** Compressed page: %u in find_get_page **\n", offset);
  			ch=page;
! 			//if (!bit_spin_trylock(PG_locked, &ch->flags)) {
! 			if (TestSetPageLocked(ch)) {
! 				printk("<1> ** WAIT DEC page: %u mapping %p **\n", offset, mapping);
! 				wait_on_chunk_head(ch);
! 				//wait_on_bit(&ch->flags, PG_locked, chunk_head_wait, TASK_UNINTERRUPTIBLE);
! 				//bit_spin_lock(PG_locked, &ch->flags);
! 				printk("<1> ** WAIT OVER got page: %p\n", ch->mapping);
! 				page=(struct page*)(ch->mapping);
! 				//bit_spin_unlock(PG_locked, &ch->flags);
! 				page_cache_get(page);
! 			} else {
! 				if (ch->mapping!=NULL) {
! 					page=(struct page *)(ch->mapping);
! 					printk("<1> GOT Page: %u; mapping %p\n", offset, mapping);
! 					page_cache_get(page);
! 					wake_up_bit(&ch->flags, PG_locked);
! 					//bit_spin_unlock(PG_locked, &ch->flags);
! 					//unlock_page(ch);
! 					goto out;
! 				}
! 				printk("<1> DEC Page: %u; mapping %p\n", offset, mapping);
! 				// decompress() routine below
! 				ch->mapping=(struct address_space *)page_private(ch);
! 				//printk("<1> GIVEN mapping %p\n", ch->mapping);
! 				page=(struct page *)(ch->mapping);
! 				wake_up_bit(&ch->flags, PG_locked);
! 
! 				//bit_spin_unlock(PG_locked, &ch->flags);
! 				//ClearPageLocked(ch);
! 				//unlock_page(ch);
! 
! 
! 				//page=(struct page *)page_private(ch);
! 				write_lock_irq(&mapping->tree_lock);
! 				radix_tree_delete(&mapping->page_tree, offset);
! 				radix_tree_insert(&mapping->page_tree, offset, page);
! 				page_cache_get(page);
! 				write_unlock_irq(&mapping->tree_lock);
! 			}
  		}
  	}
! out:
! 	if (!page) read_unlock_irq(&mapping->tree_lock);
! 	//write_unlock_irq(&mapping->tree_lock);
  	return page;
  }

Index: vmscan.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux26/mm/vmscan.c,v
retrieving revision 1.10
retrieving revision 1.11
diff -C2 -r1.10 -r1.11
*** vmscan.c	25 Mar 2006 18:58:47 -0000	1.10
--- vmscan.c	5 Apr 2006 09:36:39 -0000	1.11
***************
*** 325,329 ****
  	if (PageDirty(page)) return 0;	// PG_uptodate && PG_dirty possible?
  	if (PageUptodate(page) && PageMappedToDisk(page)) return 1;
! 	printk("FLAGS %u\n", page->flags);
  	return 0;
  }
--- 325,329 ----
  	if (PageDirty(page)) return 0;	// PG_uptodate && PG_dirty possible?
  	if (PageUptodate(page) && PageMappedToDisk(page)) return 1;
! 	//printk("FLAGS %u\n", page->flags);
  	return 0;
  }
***************
*** 337,341 ****
  	//struct chunk_head *ch;
  	mapping=page_mapping(page);
! 	//printk ("<1> Add to CCache called: mapping=%p\n", mapping);
  	if (!mapping) {
  		printk ("<1> 	orig page->count=%d\n", atomic_read(&page->_count));
--- 337,341 ----
  	//struct chunk_head *ch;
  	mapping=page_mapping(page);
! 	printk ("<1> ATC: M:%p\n", mapping);
  	if (!mapping) {
  		printk ("<1> 	orig page->count=%d\n", atomic_read(&page->_count));
***************
*** 366,369 ****
--- 366,371 ----
  	ch = kmalloc(sizeof(struct page), GFP_KERNEL);
  	if (!ch) goto out;
+ 	//printk("<1> CH Flags init: %u\n", ch->flags);
+ 	ch->flags=0;
  
  	write_lock_irq(&mapping->tree_lock);
***************
*** 375,380 ****
  	SetPageCompressed(ch);
  
! 	ch->mapping=mapping;
! 	//ch->mapping=NULL;
  	ch->index=page->index;
  
--- 377,382 ----
  	SetPageCompressed(ch);
  
! 	//ch->mapping=mapping;
! 	ch->mapping=NULL;
  	ch->index=page->index;